In general, a test handler is an apparatus for supporting a tester for testing semiconductor devices fabricated through a preset manufacturing process. The test handler classifies the fabricated semiconductor devices into several classes according to their test results and serves to unload those classified semiconductor devices onto customer trays. Such a test hander has been already known through various published documents.
FIG. 1 shows a schematic perspective view of a conventional test hander 100, and FIG. 2 sets forth a conceptual top view showing major components of the test handler 100. Below, the major components of the conventional test handler 100 will be described schematically with reference to FIGS. 1 and 2. Referring to FIG. 1, the conventional test handler 100 includes a loading unit 110, a soak chamber 120, a test chamber 130, a desoak chamber 140, an unloading unit 150 and a pushing unit 160. Further, as shown in FIG. 2, disposed behind the test chamber 130 is a tester 170 for testing semiconductor devices placed on a test tray in the test chamber 130.
The loading unit 110 transfers and loads semiconductor devices from customer trays 10a onto the test tray.
After completing the loading of the semiconductor devices on the test tray by means of the loading unit 110, the soak chamber 120 accommodates the test tray therein. The soak chamber 120 has a temperature environment for pre-heating or pre-cooling the semiconductor devices loaded on the test tray. The test tray introduced into the soak chamber 120 is translated toward the test chamber 130 while being vertically maintained. During the time period when the test tray is translated, the semiconductor devices loaded on the test tray are pre-heated or pre-cooled sufficiently.
The test chamber 130 is installed to test the semiconductor devices loaded on two test trays 11a and 11b provided from the soak chamber 120. For the purpose, the test chamber 130 has a temperature environment adequate for testing of the semiconductor devices.
The desoak chamber (so called a recovery chamber) 140 is installed to return the temperature of the heated or cooled semiconductor devices to the room temperature. The unloading unit 150 classifies the semiconductor devices on the test tray that is provided thereto via the desoak chamber 140, and it transfers and loads the classified semiconductor devices onto the customer trays 10b. 
The pushing unit 160 pushes the test trays 11a and 11b toward the tester 170.
Meanwhile, the tester 170 configured to correspond to the test handler 100 is disposed behind the test chamber 130, and it tests the semiconductor devices loaded on the test trays 11a and 11b vertically arranged in two levels in the test chamber 130.
FIG. 3 is a schematic view of the tester 170. As shown in FIG. 3, the tester 170 includes Hi-Fix boards 171a and 171b each having a number of test sockets 171-1 arranged in a matrix pattern; a test head 172; and so forth. Recently, in a test handler in general, two test trays are disposed at an upper and a lower part of a test chamber to test all the semiconductor devices loaded on the two test trays at one time by using a single tester, for the purpose of increasing a throughput. Accordingly, the tester 170 has a configuration in which the two Hi-Fix boards 171a and 171b are vertically arranged in two levels on the single test head 172, and each of the Hi-Fix boards 171a and 171b is configured to correspond to one of the test trays 11a and 11b, respectively.
FIG. 4 is a perspective view of a test tray 11. The test tray 11 includes a number of inserts 11-1 arranged in a matrix pattern to correspond to the test sockets 171-1 disposed in the matrix pattern; a frame 11-2 for supporting the inserts 11-1; and so forth. The inserts 11-1 are supported on the frame 11-2, wherein preset intervals are maintained between the inserts 11-1 in all directions.
In the above configuration, the testing of the semiconductor devices held by the inserts 11-1 of the test tray 11 can be conducted by bringing the semiconductor devices into firm contact with the test sockets 171-1 (see Korean Patent Publication No. 2000-0003128). Accordingly, the test handler 100 needs to have the pushing unit 160 for pushing the test trays 11a and 11b to the tester 170 in order to allow the semiconductor devices, which are held by the inserts 11-1 on the test trays 11a and 11b in the test chamber 130, to contact with the test sockets 171-1.
FIG. 5 is an exploded perspective view of the pushing unit 160 in accordance with the prior art. The pushing unit 160 includes a press unit 161, a plurality of guide rails 162a to 162c, match plates 163a and 163b, and so forth.
The press unit 161 has a duct 161a and a cylinder 161b for moving the duct 161a back and forth.
The guide rails 162a to 162c are fixed at an upper end portion, a middle portion and a lower end portion of the duct 161a, respectively, via screws or the like. The upper guide rail 162a is provided with a rail groove 162a-1 at a lower surface thereof; the middle guide rail 162b is provided with a rail groove 162b-1 and a rail groove 162b-2 at an upper and a lower surface thereof, respectively; and the lower guide rail 162c is provided with a rail groove 162c-1 at an upper surface thereof. The match plates 163a and 163b are installed to the guide rails 162a to 162c. 
The match plates 163a and 163b have a number of protuberant pushers 163-1 arranged in a matrix pattern to correspond to the inserts 11-1 arranged in the matrix pattern on the test trays 11a and 11b. By being supported by the guide rails 162a to 162c, the match plates 163a and 163b are fastened to the duct 161a. The match plates 163a and 163b are installed by being guided on the rail grooves 162a-1, 162b-1, 162b-2 and 162c-1, which are formed on the guide rails 162a to 162c, from the lateral side of the duct 161a. 
FIG. 6 is a side view showing a configuration in which the match plates 163a and 163b are installed to the guide rails 162a to 162c. Referring to A, B, and C portions of FIG. 6, the lower ends of the match plates 163a and 163b are configured to contact the bottom surfaces of the rail grooves 162b-1 and 162c-1 formed at the guide rails 162b and 162c, respectively, whereas certain gaps are maintained between the upper ends of the match plates 163a and 163b and the rail grooves 162a-1 and 162b-2, respectively. The gaps are provided by considering thermal expansions or contractions of the match plates 163a and 163b that may occur depending on a temperature condition within the test chamber 130.
Meanwhile, in order to allow the semiconductor devices loaded in the inserts 11-1 to be appropriately contacted with the test sockets 171-1 such that a test of the semiconductor devices can be conducted, it is required to perform a step of pushing the test trays 11a and 11b toward the tester 170 side after the match plates 163a and 163b come into firm contact with the test trays 11a and 11b, thus allowing the semiconductor devices loaded in the inserts 11 to be contacted with the test sockets 171-1. To perform such step, mechanical configurations as follows are required. The configurations will be described with reference to FIG. 7.
FIG. 7 illustrates a pusher 163-1 of the match plates 163a and 163b, an insert 11-1 of the test trays 11a and 11b, and a test socket 171-1 of the Hi-Fix boards 171a and 171b in detail.
As shown in FIG. 7, the pusher 163-1 has two pusher protrusions 163-11 for guiding an appropriate insertion of the pusher 163-1 with the insert 11-1, and the insert 11-1 is provided with two protrusion holes 11-11 for allowing the pusher protrusions 163-11 to be inserted therethrough. Here, the inner diameter of the protrusion holes 11-11 is set to be larger than the outer diameter of the pusher protrusions 163-11 in order to allow the pusher 163-1 and the insert 11-1 to appropriately contact with each other even in case the match plates 163a and 163b and the test trays 11a and 11b suffer a change in their relative sizes as a result of their thermal expansions or contractions.
Further, as illustrated in FIG. 7, the test socket 171-1 has two socket guiders 171-11 of a protrusion shape, and the insert 11-1 is provided with two guide holes 11-12 into which the socket guider 171-11 is to be firmly inserted. In such configuration, when the match plates 163a and 163b operate to push the test trays 11a and 11b toward the tester 170, the pusher protrusions 163-11 are first inserted into the protrusion holes 11-11, thus guiding the pusher 163-1 to contact with the insert 11-1. Then, the socket guiders 171-11 are inserted into the guide holes 11-12, thus guiding a semiconductor device loaded in the insert 11-1 to be contacted with the test socket 171-1.
In the above conventional configuration, however, as the sizes of the match plates 163a and 163b and the test trays 11a and 11b are changed due to their thermal expansions or contractions, an appropriate contact therebetween might not be achieved. That is, given that the test chamber 130 has a poor temperature environment (ranging from about −35 to 130 degrees) to test the semiconductor devices, the test trays 11a and 11b and the match plates 163a and 163b are subjected to thermal expansion or contraction. In contrast, as for the Hi-Fix boards 171a and 171b made up of an epoxy material, they experience little thermal expansion or contraction in comparison with the test trays 11a and 11b and the match plates 163a and 163b. The thermal expansion or contraction of the match plates 163a and 163b or the test trays 11a and 11b may cause many problems, which will be explained as follows.
In general, the match plates 163a and 163b and the frames 11-2 of the test trays 11a and 11b are made up of metal materials. The match plates 163a and 163b and the frames 11-2 of the test trays 11a and 11b may be formed of the same metal material or different metal materials. In contrast, the Hi-Fix boards 171a and 171b are formed of an epoxy material, so that it can be assumed that the Hi-Fix boards 171a and 171b hardly suffer a thermal expansion or contraction in comparison with the match plates 163a and 163b or the test trays 11a and 11b. 
If the match plates 163a and 163b and the frames 11-2 of the test trays 11a and 11b are made up of the same metal material or if a difference in the degrees of their thermal expansions or contractions is relatively small so that the pusher protrusions 163-11 can be still inserted into the protrusion holes 11-11 appropriately, and if the Hi-Fix boards hardly suffers a thermal deformation, the pushers 163-1 can appropriately contact with the inserts 11-1. However, even in such case, the guide holes 11-12 of the inserts 11-1 and the socket guiders 171-11 might be mismatched as a result of the thermal expansions or contractions of the match plates 163a and 163b and the test trays 11a and 11b. In general, since the lower ends of the match plates 163a and 163b are supported by the guide rails 162b and 162c, and the lower ends of the test trays 163a and 163b are supported by move rails (not shown), those thermal expansions or contractions cause changes in the positions of the upper ends of the match plates 163a and 163b and the test trays 11a and 11b. Accordingly, the pushers 163-1 located at upper portions of the match plates 163a and 163b and the inserts 11-1 located at upper portions of the test trays 11a and 11b may suffer a greater variation in their locations, i.e., a greater deviation in their locations, so that mismatches may be caused between the guide holes 11-12 of the inserts 11-1 provided at the upper positions of the test trays 11a and 11b and the socket guiders 171-11 of the test sockets 171-1 provided at the upper positions of the Hi-Fix boards 171a and 171b, as shown in FIG. 8, resulting in damages of the inserts 11-1 or failures of the test sockets 171-1 during the pushing operation.
Meanwhile, it is also possible to consider a condition where the degrees of the thermal expansions or contractions of the match plates 163a and 163b and the test trays 11a and 11b are different, and a mismatch occurs between the pusher protrusions 163-11 provided at the upper portions of the match plates 163a and 163b and the protrusion holes 11-11 provided at the upper portions of the test trays 11a and 11b so that the pusher protrusions 163-11 cannot be inserted into the protrusion holes 11-11, which results in a failure to firmly adhere the match plates 163a and 163b to the test trays 11a and 11b. 
FIG. 9 shows an example where the match plates 163a and 163b cannot be firmly adhered to the test trays 11a and 11b by assuming that the test trays 11a and 11b are made up of a material which does not suffer a thermal expansion or contraction while the match plates 163a and 163b are made up of a material suffering a great thermal expansion or contraction. In the case of FIG. 9, before the semiconductor devices loaded in the inserts 11-1 and the test sockets 171-1 come into appropriate contact with each other, there occurs a mismatch problem between the pushers 163-1 disposed at the upper portions of the match plates 163a and 163b and the inserts 11-1 disposed at the upper portions of the test trays 11a and 11b. As a result, the semiconductor devices loaded in the inserts 11-1 and the test sockets 171-1 cannot contact appropriately.
Besides, when considering the recent trend for the development of the test handler that the sizes of the test tray is increased to test more semiconductor devices at one time, the above-cited problem relevant to thermal expansion or contraction would become an even more serious problem yet to be solved.